**Extended comments highlighted in blue.
Corn silage is one of the unique feeds in our livestock diets. It is universally grown in almost all of our dairy production areas.
Corn is a focus of our agricultural system, receiving its share of research and development resources. Corn for silage is a benefactor of that focus, resulting in huge improvements in yields, feed quality and better production systems. Every fall, farms across the country will each harvest from a few hundred tons to thousands of tons of corn silage.
But corn silage is not all the same. It can range from a fibrous diet filler to a truly high-energy, "high-octane" feed.
At this time of year, factors such as variety selection and growing practice are already in place. But there are still many harvesting decisions and practices that can have a profound effect on the final feeding value of the crop.
The first is timing of the harvest. The objective is to find the right stage of maturity. You want to enable the accumulation of starch and balance it with the quality of the fiber. This maximizes the digestible fractions and minimizes the lignin, yet maintains sufficient moisture to permit fermentation.
I have used several parameters to judge the right time to let the choppers roll. The most common approach during the last few years has been to monitor the whole-plant moisture content. The guideline is 30% to 32%. At that moisture level, under most situations, the harvested silage is about right.
However, leaving the corn plant in the field a few more days and letting the moisture level drop a few extra points allows the plant to mature a little more. The result is that some additional starch is deposited in the grain, increasing the energy value of the silage.
Everything has its tradeoffs. In the case of corn silage, more grain and starch in the silage has to be balanced against the possibility of the plant becoming too dry for good fermentation and preservation. For large-acreage producers, it also decreases the window of time to get a large crop in the bunk. All of these concerns can be overcome with good planning and management.
Here’s the recipe for high-octane silage:
Target an extra three or four percentage points of dry matter for your silage harvest. This will vary depending on which part of the country you are in. It will also shorten your harvest window. You cannot let the harvest get beyond the point of adequate moisture to support good fermentation. A good harvest monitoring system needs to be in place so you will know the moisture of the silage coming into the bunk on a daily basis.
Dryer corn silage requires better chopping and processing. A 3⁄8" cut works well as long as everything is cut 3⁄8". Dull knives smash and grind, leaving a lot of smaller and larger particles in the mix.
- June/July 2012